Modular drinking water filtration system with bottom load cartridges with grip-enhanced end rings and color coding

ABSTRACT

An assembly method and related subassembly for a water filter element in the housing of a replaceable filter cartridge provides for filter element insertion into the open bottom end of the housing and subsequent attachment of a retaining ring to the upper end of the element such that the element is secured against vertical drop-out until the bottom end of the cartridge can be enclosed with an end cap. The method and subassembly are particularly well adapted to cartridges in which the lower end cap is attached by spin welding. The enclosing end cap may also be provided with end rings to enhance the user&#39;s grip in cartridge installation and removal. The end rings may also be color coded for each of cartridge identification and matching to the filter head.

BACKGROUND OF THE INVENTION

The present invention pertains to a drinking water purification systemand, more particularly, to a modular system for under-counter orunder-sink installation using replaceable cartridges and which may beconfigured in a system utilizing up to four cartridges, including areverse osmosis (RO) cartridge.

A drinking water filter system adapted for under-counter mounting isshown in U.S. Pat. No. 6,436,282. The system is disclosed with threereplaceable filter cartridges, one of which is an RO filter cartridge.The three cartridges are connected to a common header, but thedissimilarity between the three cartridges may require the use of adifferent attachment head within the header for each filter cartridge.Also, the header is designed for three cartridges, whereas it would bedesirable to have a modular system utilizing from one to four filtercartridges, depending on the particular application.

It would also be desirable to have a modular system that could utilizefrom one to four separate filter cartridges, one of which could be an ROcartridge, in which the system could be assembled by the manufacturer orseller using identical filter heads and modularly connected mountingdevices. Most cartridges could be provided with mounting arrangementsand flow connections using the same head with the heads seriallyinterconnected to form the desired configuration. An RO cartridgerequiring a non-standard head could be designed for use in the modularassembly. It would also be desirable to have a modular system in which aproprietary fit could be provided that matches the filter cartridge tothe head to assure proper fit.

The modular system described above, lends itself to an under-sink orunder-counter system that is easy to install and provides easy cartridgereplacement. Applying this modular design to the system of the presentinvention also provides the ability to utilize common filter heads withidentical internal flow valve spindles that are controlled by attachmentand removal of the filter cartridge, a simple and effective way ofproviding a seal between the spindle and the head, customizable keyarrangement between the filter cartridge and the head that can beutilized to provide a proprietary feature for a seller and to assure useof the proper replacement cartridge, the ability to easily remove andreplace the RO control valve in a special RO cartridge and head, andspecial assembly techniques that facilitate assembly of filtercartridges, including axially aligned inlet and outlet, color coded endrings and high friction end caps for facilitating cartridge replacement.

SUMMARY OF THE INVENTION

The present invention, in its various aspects, is applied to thecombination of a replaceable water filter cartridge that has a filterbody with an axially extending neck on one end, the neck having an inletand an outlet for water, and a filter head that has an outer housingdefining a cylindrical interior wall with an inlet opening for water tobe treated and an outlet opening for treated water. A valve spindle isdisposed in the outer housing for reciprocal rotary movement on thefilter body axis between flow and no-flow positions, whereby connectionand disconnection of the outer housing inlet opening and outlet openingwith the cartridge inlet and outlet are provided. The spindle has aninterior chamber for receipt of the cartridge neck to provide the flowconnection and disconnection.

In accordance with one aspect of the present invention, an improved flowpath and seal arrangement is provided whereby the spindle has acylindrical outer wall portion that is positioned in closely spacedcoaxial relation to the cylindrical interior wall of the outer housing;a pair of diametrically opposed and coaxially aligned flow ports areprovided in the spindle outer wall portion which are aligned with theouter housing inlet and outlet openings in the flow position and out ofalignment with those openings in the no-flow position; a unitary dualfunction seal is provided for each flow port, with each seal supportedon the spindle outer wall portion and having an inner peripheral sealingrib that surrounds the flow port in the flow position and is in sealingengagement with the cylindrical interior wall of the outer housing inboth the flow and no-flow positions, and an outer peripheral sealing ribsurrounding the inner sealing rib and constructed and positioned to bein sealing engagement with the interior wall of the outer housing inboth the flow and no-flow positions, the inner and outer ribs togetherpreventing flow in the no-flow position.

The improved flow path and seal arrangement preferably includes amounting recess in the face of the spindle outer wall portion in whichthe inner and outer sealing ribs of the seal are received. Anintermediate web connects the inner and outer sealing ribs and is seatedin the mounting recess. The inner rib is preferably circular in shape,and the mounting recess is provided with an integral cylindrical nipplethat defines the flow port and extends radially outward into sealing andsupporting contact with the seal inner rib.

In accordance with another aspect of the invention, an arrangement isprovided to assure compatibility and operative connection of thecartridge to the filter head. The arrangement includes a first adaptorring that has a first half of a locator device formed thereon, the firstadaptor ring is mounted in the head coaxially with the interior wallwith the first half of the locator device positioned at acircumferentially selected position. A second adaptor ring has a secondhalf of the locator device formed thereon, the second adaptor ring ismounted on the filter cartridge surrounding the neck and coaxiallytherewith. The second half of the locator device is positioned at acircumferentially selected position to engage the first half and topermit operative connection of the cartridge to the head.

In a presently preferred embodiment, the upper adaptor ring and thelower adaptor ring are provided with integral weld flanges that seat inrespective complementary weld grooves in the spindle and on the neck ofthe cartridge body. The rings are secured by spin welding. The exposedface of the upper adaptor ring have a pair of diametrically oppositeaxial extending fingers that engage a pair of diametrically oppositerecesses in the lower adaptor ring to ensure compatibility between thefilter cartridge and the head. The upper and lower adaptor rings may beselectively circumferentially repositioned to provide a proprietary fitfor selected customers. Further, the position of the fingers andcomplementary recesses may be varied radially on the ring surfaces toprovide an even broader range of proprietary fits.

In another embodiment, the first half of the locator device comprises afirst axially facing non-planar surface that defines a first axiallyextending abutment face. The second half of the locator device comprisesa second axially facing non-planar surface that complements the firstnon-planar surface and defines an oppositely facing second axiallyextending abutment face. Relative rotation and axial displacement of thecartridge on its axis and with respect to the filter head interior wallresults in engagement of the abutment faces. It is particularlypreferred to use diametrically opposed pairs of first and second halvesof the locator device.

One of the axially facing non-planar surfaces has an axial protrusionthat defines the abutment face, and the other axially facing non-planarsurface has an axial recess that defines the abutment face. Preferably,the filter head comprises an outer housing that defines an innercylindrical wall having an inlet opening for water to be treated and anoutlet opening for treated water. A valve spindle is rotatably disposedin the outer housing for rotary reciprocal movement between flow andno-flow positions that connect and disconnect the outer housing inletopening and outlet opening with the cartridge inlet and outlet,respectively. The valve spindle defines the cylindrical interior wallfor receipt of the cartridge neck.

The first adaptor ring is attached to a first mounting surface on thecylindrical interior wall of the valve spindle, and the second adaptorring is attached to a second mounting surface on the neck of the filterbody. The first and second mounting surfaces comprise annular shouldersof generally the same diameter. The adaptor rings are preferablyattached to their respective mounting surfaces with welds, preferablyfriction welds, and more preferably spin welds. The adaptor rings arepositioned circumferentially to assure engagement of the second abutmentface of a selected filter cartridge with the first abutment face in thespindle.

In a variant embodiment, the first half of the locator device comprisesa notch formed in the first adaptor ring, and the second half of thelocator device comprises an axially extending finger on the secondadaptor ring, the finger sized and positioned to engage the notch toestablish operative connection. A housing is provided for the filterbody that has a circular open end through which the neck of the filterbody extends. An annular end cap interconnects the filter body and theneck and provides a sealed connection to the open end of the housing ina fully assembled state. An orientation recess is provided in the endcap to engage with a complementary orientation tab on the inside of thehousing open end. The tab is received in the recess in the fullyassembled state to fix the circumferentially selected position of thefinger on the second adaptor ring. The adaptor rings in this embodimentare attached with welds, preferably ultrasonic welds.

In accordance with another aspect of the present invention, anarrangement is provided for mounting the filter head and demountablysupporting the filter cartridge, the arrangement includes a mountingbracket and an integral mounting ring. The improved arrangement includesa filter head outer housing with a pair of oppositely extending coaxialsleeves that define the inlet opening and the outlet opening. A mountinglug arrangement is provided on the filter head outer housing and acooperating slot arrangement is provided on the mounting ring to permitthe housing and valve spindle to be connected and locked to the mountingring in an operative position. The outer housing has a lower cylindricalskirt and the lug arrangement includes a pair of diametrically oppositemounting lugs that are integrally formed on the lower edge of the skirt.The mounting ring has an annular recess for receipt of the housingcylindrical skirt and a pair of slots for receipt of the mounting lugs,one of the mounting lugs adapted to fit in only one of the slots toassure proper flow orientation of the co-axial inlet and outlet sleeves.A circular track in the mounting ring annular recess is dimensioned toreceive the mounting lugs in response to rotation of the outer housingin the recess, and a stop detent on the cylindrical skirt overrides andengages a first stop in the track to prevent reverse rotation andestablish the operative position. In addition, a locking detent isprovided on the cylindrical skirt to engage a second stop in the track,the second stop preventing reverse rotation of the outer housing fromthe operative position.

The apparatus also includes an arrangement for operatively attaching thefilter cartridge to the mounting ring and the filter head. In thisarrangement, a pair of opposed attachment lugs are provided on the neckof the filter cartridge, a pair of entrance slots are provided in thelower edge of the mounting ring for receipt of the attachment lugs uponvertical upward axial movement of the cartridge neck into the filterhead. The entrance slots terminate in an annular shoulder that isengageable by and supports the attachment lugs in response to rotationalmovement of the attachment lugs along the shoulder relative to themounting rings. The filter cartridge is thereby supported in anoperative position by the mounting ring. Preferably, the lead ends ofthe attachment lugs, in the rotational direction, are provided withtapered faces and the entrance slots are provided with cooperatingramped faces to facilitate axial and rotational movement of thecartridge.

Preferably, the lower end of the valve spindle is provided with aspindle skirt in the lower edge of which is provided a pair of notches.Cooperating semi-annular recesses are formed in the inner lower edge ofthe outer housing skirt to receive the attachment lugs. The notches haveend faces that are engageable by the lead ends of the attachment lugs inresponse to rotational movement of the lugs to establish a rotationallimit of the filter cartridge and the operational position thereof.

In a related embodiment, the mounting bracket is preferably rectangularin shape, and the mounting arrangement includes a modular back platethat has a generally planar base and a front mounting face having anopen-ended mounting slot defined by parallel tracks. The mounting slotis adapted to receive the edges of the mounting bracket as it isinserted into the open-ended slot, and a bracket stop is engageable bythe mounting bracket upon full insertion thereof into the slot.Preferably, the bracket stop comprises a notch in one edge of themounting bracket engageable by a detent in the associated track. Theback plates are preferably provided with parallel opposite edges thathave complimentary engagement devices for modular interlockingconnection of adjacent back plates.

The face of the back plate extends away from the mounting slot andincludes a reinforcing guide arrangement adapted to engage andfacilitate axial alignment of the filter cartridge body for attachmentto the mounting ring, and to stiffen the mounting bracket. Preferably,the reinforcing guide arrangement comprises a pair of spacer panelsextending perpendicularly from the mounting face and a series of spacedgussets connected to the mounting face, the panels support a cradlebetween the panels for supporting the filter cartridge body.

The mounting arrangement also includes a cover that has a hingedconnection to the back plate along one edge adjacent the filter head.The opposite edge of the cover has a latching connection to the otheredge of the back plate. The cover encloses the filter head and themounting ring and has passages that are axially aligned, in the latchedposition, with the mounting ring. This arrangement allows the filtercartridge to be removable and replaceable through the passages in thecover by manual engagement of the free end of the cartridge. The sideedges of the cover preferably include complementary connecting devicesto provide modular interlocking of adjacent covers.

In accordance with another aspect of the present invention, anarrangement is provided for the removal and replacement of a specialspindle for use with a reverse osmosis or other semi-permeable membranefilter cartridge. The valve spindle for use with an RO cartridge housesa special dual diaphragm shut off valve that is replaceable with thespindle. In this embodiment, the spindle is demountably locked to thefilter head outer housing. A spindle lock arrangement includes anannular groove in an exterior wall of the spindle, preferably above thedual function seals. The exterior spindle wall is coaxial with thespindle outer wall portion and the groove is provided with a slot thatforms an axially extending passage therethrough. A lug on the interiorof the filter head outer housing is received in the groove and holds thespindle against axial displacement from the filter head housing over arange of spindle rotation including spindle movement between the flowand no-flow positions. The lug is adapted to move circumferentially inand relative to the annular groove and axially relative to and throughthe slot in response to disconnection of the filter cartridge, manualrotation of the spindle beyond the above identified range, and axialmovement of the spindle out of the outer housing.

The filter cartridge comprises a semi-permeable membrane filter. Thesemi-permeable membrane may comprise an ultra filter membrane or areverse osmosis membrane.

The mounting ring for the filter head and cartridge includes an annularrecess for receipt in one axial direction and attachment of the filterhead housing, and for receipt in the opposite axial direction anddemountable attachment of the filter cartridge neck. The filter housingand cartridge neck capture the spindle in an operative positiontherebetween. The apparatus is preferably provided with a manuallyoperable removal tool that has a spindle engagement lug on one axial endthat is adapted to engage the spindle to overcome seal friction andfacilitate spindle removal.

The water filter elements used in the apparatus of the present inventionare carried in housings of similar size and shape to accommodate modularconstruction in addition to convenient replaceability. A preferredmethod for assembling a water filter element in a housing for such areplaceable filter cartridge utilizes a housing that has an openoperative end defined by an annular reduced diameter portion. The filterelement has an end closure with an axially extending neck that sealinglyengages the interior of the reduced diameter portion of the housing andincludes an end that extends axially past the reduced diameter portion.The engagement of the filter element with the interior of the reduceddiameter portion of the housing defines a stop position. The neck alsohas an inlet and an outlet for water. The assembly method includes thesteps of (1) providing the opposite end of the housing with an annularopening for receipt of the filter element, (2) inserting the filterelement axially through the annular opening until the element reachesthe stop position, (3) attaching a retaining ring to the neck of thefilter element at a position axially beyond and in engagement with theend of the reduced diameter portion of the housing when the filterelement is in the stop position to retain the element from reverse axialmovement, and (4) attaching a housing end cap to the annular opening inthe housing to seal the opening and to hold the filter element in thestop position.

The foregoing method preferably includes the steps of (1) providing anannular groove in the neck of the filter element, and (2) placing theretaining ring in the annular groove. The retaining ring preferablycomprises an O-ring.

The method also preferably includes attaching the housing end cap byspin welding. Ultrasonic welding may also be used. It is also preferredto attach a cap grip to the housing end cap which cap grip may includethe step of coding the cap grip with cartridge identification indicia.Such indicia may comprise color coding. The attaching step may comprisesnap fitting and the grip preferably is provided with a high frictionsurface to enhance manual gripping.

A subassembly provided by the foregoing assembly method includes acylindrical housing that has an opening having an open operative enddefined by an annular reduced diameter portion and an annular opening inthe opposite end of a diameter larger than the diameter of the openoperative end. A filter element is positioned in the housing and has anend closure with an axially extending neck making sealing contact withthe interior of the reduced diameter portion. The filter element has amajor diameter smaller than the annular opening and larger than the openoperative end such that the filter element is positioned in the housingagainst an axial stop to define an operative position. A retaining ringis attached to the filter element neck at a position axially beyond andin engagement with the end of the reduced diameter portion of thehousing to retain the element against axial movement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a drinking water filtration systemutilizing the modular construction of the present invention.

FIG. 2 is a side elevation view of the system shown in FIG. 1.

FIG. 3 is perspective view of the filter system with the enclosinghousing opened to show features of the system construction.

FIG. 4 is an exploded perspective view of the mounting bracket andfilter head subassembly.

FIG. 5 is a perspective view of the subassembly shown in FIG. 4 with thefilter head attached to the mounting bracket.

FIG. 6 is a vertical section of the subassembly shown in FIG. 5,additionally showing the valve spindle.

FIG. 7 is horizontal section taken on line 7-7 of FIG. 5.

FIG. 8A is an exploded elevation view of the filter head, mountingracket and filter cartridge assembly.

FIG. 8B is an exploded vertical section of the head, mounting bracketand filter cartridge assembly taken on line 8B-8B of GI. 8A.

FIG. 9 is a perspective view of the valve spindle shown in FIGS. 6 and8.

FIG. 10 is a perspective view similar to FIG. 9 and additionally showingthe dual function seal.

FIGS. 11 and 12 are perspective views of complementary adaptor rings foruse in the filter assembly of FIG. 8

FIGS. 11A and 12A are perspective views of an alternate embodiment ofthe adaptor rings shown in FIG. 8.

FIG. 13 is a vertical section through an embodiment of the filter systemutilizing a reverse osmosis filter cartridge.

FIG. 14 is an enlarged sectional detail of FIG. 13.

FIGS. 15A, 15B and 15C are enlarged sectional details, similar to FIG.14, but taken on different rotational vertical planes to show additionalelements of the system construction.

FIG. 16 is a top plan view of the mounting bracket and mounting ring forthe system shown in FIG. 13.

FIG. 17 is a bottom perspective view of the RO filter head used in theFIG. 14 detail.

FIG. 18 is a perspective view of the RO filter cartridge used in theFIG. 13 system.

FIG. 19 is a perspective view of the cartridge shown in FIG. 18 attachedto the mounting ring and filter head.

FIG. 20 is a perspective view of the valve spindle shown in FIGS. 14,15A and 15B.

FIG. 21 is an enlarged perspective view of the spindle drive ring shownin FIGS. 14, 15A and 15B.

FIG. 22 is an elevation view of the RO filter element.

FIG. 23 is a perspective view of the end cap for the filter elementshown in FIG. 22.

FIG. 24 is a perspective view of the adaptor ring for the filter elementshown in FIG. 22.

FIG. 25 is a perspective view of the adaptor ring for the spindle shownin FIG. 20.

FIG. 26 is a bottom plan view of the spindle shown in FIG. 20.

FIG. 27 is a perspective view of a spindle removal tool.

FIG. 28 is a perspective view of a filter element of the cartridge shownin FIG. 8.

FIG. 29 is a perspective view of the housing for the element shown inFIG. 28.

FIG. 30 is a partially exploded view of the assembly of the filterelement in FIG. 28 and housing in FIG. 29.

FIG. 31 is a vertical sectional view of another arrangement for assuringfilter compatibility and operative connection.

FIG. 32 is an enlarged view of a portion of FIG. 31 showing theunlocking of the spindle from the head.

FIG. 33 is a top plan view of the adaptor ring used in the FIG. 31arrangement.

FIG. 34 is a view similar to FIG. 32 showing the fully unlockedposition.

FIG. 35 is a perspective end view of the valve spindle and locking pinarrangement.

FIG. 36 is a perspective bottom view of the adaptor ring shown in FIG.33.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The water filter system 10 shown in FIG. 1 includes three replaceablefilter cartridges that are hydraulically connected to provide serialtreatment of untreated water entering the system via inlet 12 andexiting the system as treated water via outlet 13. Each cartridge 11forms part of an independent filter module 14 that can function as aseparate filter unit or, as shown, be connected to adjacent modules 14to form a system including as many as four or more cartridge modules.Furthermore, the cartridges 11 chosen for use in the modular system 10can perform widely varying filter functions. For example, in the systemshown, the first cartridge directly receiving untreated water throughthe inlet 12 may comprise a granular activated carbon filter element.The second cartridge, receiving pretreated water from the firstcartridge may comprise a reverse osmosis (RO) filter unit, and the thirdcartridge 17 may comprise a final or polishing filter that receivesfiltered water directly from the RO filter 16 (or from a pressurizedstorage tank, not shown) from which it is discharged for use via thetreated water outlet 13.

The filter system 10 shown in FIG. 1 is mounted with the filtercartridges 11 disposed vertically on their axes, but an importantfeature of the present invention permits the attachment of a modularlyconstructed system at virtually any orientation of the cartridges.Furthermore, as will be explained in greater detail, the modular filtersystem 10 lends itself well to custom assembly of the system to meet acustomer's particular needs in a manner utilizing common parts andconvenient interconnection.

Each filter module 14 includes a back plate 18 that comprises the mainsupport structure and provides the means for mounting the module to anyconvenient flat surface, such as the inside surface of a cupboard belowa sink. The back plate 18 has a generally planar base 20 that includes apair of spaced universal mounting openings 21 for convenient attachmentof the back plate to the supporting surface. The front face of the backplate 18 has an open-ended mounting slot 22 defined by a pair ofparallel tracks 23. The mounting slot tracks 23 are sized to receive theedges of a rectangular mounting bracket 24 that carries an integralmounting ring 25. The mounting ring 25 provides support for and aninterconnection of a cartridge 11 and a filter head 26, whichinterconnection will be described in greater detail below.

The mounting bracket 24, carrying the mounting ring 25, is slid into thetracks 23 defining the mounting slot 22 until an internal bracket stopis engaged when the mounting bracket is fully inserted. The bracket stopmay comprise a notch 27 in one edge of the bracket that is engaged by adetent 28 in the associated track 23 when the bracket is fully inserted.Because the mounting slot 22 is open ended on both ends, the mountingbracket 24 may be slid directly through the mounting slot 22 on one backplate 18 and into the mounting slot on the next adjacent back plate bymanually overcoming the locking provided by the bracket stop 29 andmoving the mounting bracket linearly.

The side edges 30 of the back plates 18 are provided with complementaryhook-and-slot edge connectors 31, enabling adjacent back plates to beinterconnected to provide a modular construction. A portion of the backplate base 20 provided with a reinforcing and cartridge guidearrangement 32 that includes a pair of spacer panels 33 that includestiffening gussets 34 and between which is supported a cradle 35 thathelps support and guide the cartridge 11 as it is inserted through themounting ring 25 and into operative engagement with the filter head 26.Certain of the stiffening gussets 34 are also provided withhook-and-slot edge connectors 36 to help provide rigidity in the modularassembly of back plates 18.

Adjacent filter heads 26 are interconnected with flexible tubularconnectors 39. A connector 39 has one end inserted in an inlet sleeve 48in the filter head and the other end in an outlet sleeve 50 of the nextadjacent filter head. Axial alignment of the inlet and outlet sleeves 48and 50 makes connection of adjacent filter modules 14 easy and reliable.

The modular assembly of the filter system 10 is completed with anenclosing housing 37 that further helps secure the filter cartridges 11in their mounted positions, facilitates cartridge removal andreplacement and provides an aesthetic covering for the system. Thehousing is also modular insofar as each back plate 18 carries its ownhousing module 38. Each housing module has a hinged connection 40 to anedge of the back plate 18, enabling the housing module 38 to be pivotedaway from the back plate for installation of the mounting bracket 24 andfilter head 26, both of which are typically interconnected and mountedtogether by sliding the mounting bracket into the mounting slot 22.However, adjacent housing modules 38 are also interconnected so that ina fully assembled filter system 10, all of the housing modules 38 pivottogether between the open position shown in FIG. 3 and the closedposition shown in FIG. 1. Each housing module 38 has an irregular shapedwavy front face 41 that defines three oblong cartridge openings 42. Whenthe housing modules 38 are pivoted to the closed position, the edgeopposite the hinged connection 40 latches onto the edge of the backplate base 20 with a spring-lock connection 43 that can be manuallyreleased by the user to open the housing should it be necessary toaccess the filter head 26. In the closed position of the housing 37, theoblong cartridge openings 42 are axially aligned and axially alignedwith the cradle 35 and mounting ring 25, such that a filter cartridge 11may be inserted axially through the mounting ring 25 and into the filterhead 26. In the mounted position, as shown in the drawings, the free endof the filter cartridge 11 is accessible to and may be convenientlygrasped by the user to turn and remove the cartridge, as will bediscussed in greater detail below.

The wavy edges 44 of the housing front face 41 are provided withconnector openings 45 which, when adjacent housing modules 38 arealigned, can be connected with circular spade connectors 46. It will beappreciated that by use of back plate edge connectors 31, edgeconnectors 36 on adjacent spacer panels 33, the hinged connection 40 forthe housing module and spade connectors 46 for adjacent housing modules38, a very rigid assembly may be produced. Furthermore, as suggestedabove, the mounting openings 21 in the back plate base 20 permit themounting of the system in virtually any orientation that provides accessof the filter cartridges 11 to the user.

Referring now to FIGS. 4-6, the mounting ring 25 on the mounting bracket24 provides attachment for the filter head 26 and a demountable supportfor the filter cartridge 11. The filter head 26 also provides flowconnections to and from the filter cartridge, the operative end of whichis inserted axially into the filter head. The filter head includes acylindrical top portion 47 that defines an outer housing 49 carrying apair of oppositely extending coaxial sleeves 48 and 50 that define,respectively, the water inlet opening and water outlet opening to andfrom the filter head. On the interior of the filter head housing, thereis mounted a flow control valve spindle, the function of which will bedescribed in detail below.

The filter head outer housing 49 has a bottom cylindrical skirt having adiameter somewhat larger than the top portion 47. The edge of thecylindrical skirt 51 is provided with a pair of diametrically oppositemounting lugs 52 and 53. The mounting ring 25 has a generally openannular interior including an outer wall 54 sized to receive thecylindrical skirt 51 of the filter head outer housing 49. The upper edgeof the mounting ring outer wall 54 includes a pair of inwardly openingslots 55 and 56, respectively, for receipt of the mounting lugs 52 and53. Mounting lug 52, positioned below the inlet sleeve 48, is providedwith an open gap 57. The slot 55 in the mounting ring outer wall 54 hasa protrusion 58 sized to move axially through the gap 57 as the housingcylindrical skirt 51 moves axially into the mounting ring 25. Bycomparison, the housing mounting lug 53 (diametrically opposite mountinglug 52) has no gap and the slot 56 does not have a protrusion. As aresult, the filter head 26 can only be inserted into the mounting ringat one circumferential position. As the cylindrical skirt 51 of thefilter head drops through the slots, the lower edge comes to rest on acircular track 60 on the interior of the mounting ring. The track 60defines the bottom of an annular slot 61 having a height just slightlylarger than the thickness of the mounting lugs 52 and 53 such that, whenthe filter head is rotated on the circular track 60, the lugs 52 and 53pass into the annular slot 61 until the filter head is in an operativeposition with the axis of the coaxial inlet and outlet sleeves 48 and 50is parallel to the mounting bracket 24, as shown in FIG. 5. In thisposition, stop detent 62 on the cylindrical skirt 51 engages a firststop 63 in the circular track 60 to prevent reverse rotation andestablish the operative position of the filter head. Further, a lockingdetent 64 on the cylindrical skirt 51 simultaneously engages a secondstop 65 on the circular track to prevent continued rotation of thefilter head and to lock it in its operative position.

Referring to FIG. 6, the top portion 47 of the filter head 26 has acylindrical interior wall 66 in which are formed diametrically oppositeinlet opening 67 from the inlet sleeve 48 and outlet opening 68 to theoutlet sleeve 50. Referring also to FIGS. 8A and 8B, the outer housing49 of the filter head 26 houses a valve spindle 70, the reciprocalrotary movement of which controls the flow of water into and out of thefilter cartridge 11. The filter cartridge is inserted axially throughthe bottom of the mounting ring 25 where a combination of vertical axialmovement and rotational movement simultaneously locks the cartridge 11onto the mounting ring 25 and rotates the spindle 70 from the off(no-flow) position to the on (flow) position. The valve spindle 70 has acylindrical body 71 that is positioned in closely spaced coaxialrelation to the cylindrical interior wall 66 of the filter head 26. Thecylindrical spindle body 71 has a pair of diametrically opposed andcoaxially aligned flow ports 73 which move, with rotation of the spindle70, between the flow and no-flow positions to provide connection anddisconnection of the inlet and outlet openings 67 and 68 in the filterhead interior wall with the cartridge inlet and outlet, which will nowbe described.

The filter cartridge 11 has a body 74 with an axially extending neck 75on one end. The neck defines an inlet 76 for water to be treated and anoutlet 77 for water treated by flow through an interior filter element78. The neck 75 has a stepped construction including a large diametershoulder 80 adjacent the filter body 74 that has an annular shape, butis interrupted by a pair of diametrically opposed connector lugs 81. Incross section, the connector lugs 81 have a parallelogram shape withnarrow leading and trailing edges 82, in the rotational direction, thatdefine cam surfaces 83. The circular track 60 in the mounting ring 25has a pair of diametrically opposed slots 84, each of which has angledcontact surfaces 85 that define openings through which the connectorlugs 81 on the filter cartridge neck may pass. As the filter cartridgeneck 75 is inserted axially into the mounting ring 25 and spindle 70,simultaneous rotation of the cartridge to the right (in the clockwisedirection) will permit the leading cam surfaces 83 on the connector lugs81 to ride upwardly over the contact surfaces 85, into the mounting ring25 and onto the circular track 60. As the connector lugs 81 reach thisposition, their lead edges engage the edge 86 of a slot 87 in the loweredge of the spindle 70 (see also FIG. 10). Continued rotation of thefilter cartridge results in rotation of the spindle from the no-flowposition to the flow position. Further rotation of the spindle past theflow position is prevented by engagement of a stop 88 on the slot edge86 with the face 90 of a shallow groove 91 formed on the inside of thefilter head cylindrical skirt 51 (see FIG. 6). To remove the filtercartridge 11, as for replacement, the free end of the cartridge isgrasped by the user and rotated to the left (in the counterclockwisedirection), the opposite edges 82 of the connector lugs 81 engage theopposite edges 86 of the slots 87 in the edge of the spindle 70 to causerotation of the spindle in the same direction to close the valve. Whenthe connector lugs 81 reach the slots 84 in the mounting ring circulartrack 60, the lugs drop through the slots and the cartridge movesaxially out of the filter head and mounting ring.

Referring particularly to FIGS. 6, 9 and 10, the spindle 70 must beprovided with a seal arrangement that provides a water tight interfacebetween the outside of the cylindrical body 71 of the spindle and thecylindrical interior wall 66 of the filter head 26. The main sealinginterface is provided by an upper O-ring seal 92 and a lower O-ring seal93. The spindle 70 also provides an important sealing interface betweenthe flow ports 73 in the spindle and the inlet and outlet openings 67and 68 extending through the cylindrical interior wall 66 of the filterhead and the respective inlet and outlet sleeves 48 and 50. A dualfunction seal 94 is provided for each of the coaxial, diametricallyopposed flow ports 73. The seal 94 rests in a recess 95 in the body 71of the spindle. The flow ports 73 are defined by a sleeve-like nipple 96that is surrounded by an inner sealing rib 97 on the seal 94 such thatwhen the inner sealing ribs are aligned with the inlet and outletopenings 67 and 68 on the inside of the filter head, flow is enabledbetween the filter head and the cartridge, as described above. The innersealing rib 97 bears against the cylindrical interior wall 66 of thehead to seal against leakage in the flow position. The inner sealing rib97 is surrounded by an outer sealing rib 98 and connected thereto by anintermediate web 100 to provide a unitary seal that rests snuggly in therecess 95. A portion of the outer sealing rib may include a part of theinner sealing rib, as shown. When the spindle 70 is rotated to theno-flow position, the outer sealing rib 98 and a portion of the innersealing rib 97, which together surround the intermediate web 100,surround and cover the inlet and outlet openings 67 and 68 in thecylindrical interior wall of the filter head. The dual function seal 94is molded from any suitable synthetic rubber sealing material and isprovided with a slight curvature to match the spindle body 71 to fitsnuggly in the recess 95.

Referring again to FIG. 8B, with the filter cartridge 11 operativelyconnected to the filter head 26, the flow of water from the inlet sleeve48, through the flow port 73 in the spindle body, is directed into thecartridge inlet 76 comprising an annular passageway 101 in the cartridgeneck 75. The incoming water flows into the space between the filter body74 interior and the outside of the filter element 78, radially inwardlythrough the element and into the hollow interior 102 of the element.From the interior of the filter element, the filtered water flowsupwardly into the cartridge neck 75, out of an axial outlet passage 103,which comprises the cartridge outlet 77, and into the spindle 70 whereit is directed out of the flow port 73 and into the outlet sleeve 50,all as generally shown by the arrows in FIG. 8. In order to eliminate orsubstantially reduce undesirable leakage from the filter cartridge 11after it is removed from the filter head and mounting ring, an annularporous disk 104 is placed in the annular inlet passage 101 and acircular porous disk 105 is placed in the axial outlet passage 103. Thedisks preferably comprise open cell porous polypropylene bodies that areporous enough to not inhibit flow through the system under normalpressure, but which inhibit flow in the absence of pressure, as when thecartridge is removed.

Referring again to FIGS. 6, 8A and 8B, as well as to FIGS. 11 and 12 and11A and 12A, an arrangement is provided to assure filter cartridgecompatibility and operative connection of the cartridge to the filterhead. The arrangement may also be utilized to provide a proprietaryarrangement for a selected distributor or installer of filter systems inaccordance with the teaching of this invention. In one embodiment, anupper adaptor ring 106 is mounted in the spindle 70 and a lower adaptorring 107 is attached to the neck 75 of the filter cartridge 11. Therings 106 and 107 have complementary interengaging arrangements thatassure compatibility of the filter cartridge to the head.

In the embodiment shown in FIGS. 11 and 12, the upper adaptor ring 106is secured to a shoulder 108 defined by the interface between the upperspindle body 71 and a larger diameter spindle skirt 110. The adaptorring 106 is provided with an integral weld flange 111 and the mountingshoulder 108 is provided with a complementary weld groove 112. In asimilar manner, the lower adaptor ring 107 is mounted on a shoulder 113on the neck of the cartridge body 74 above the connector lugs 81. Thelower adaptor ring 107 has an integral weld flange 114 that seats in acomplementary weld groove 115 in the shoulder 113. Both rings 106 and107 are secured to the respective shoulders 108 and 113 by spin welding,ultrasonic welding or any other suitable welding process. The exposedface of the upper adaptor ring 106 is planar, except for a pair ofdiametrically opposite axially extending fingers 116. The exposed planarface of the lower adaptor ring 107 has a pair of diametrically oppositerecesses 117. The upper and lower adaptor rings are located incircumferentially precise and complementary positions such that relativerotation and axial displacement of the filter cartridge 11 as it isinserted into the spindle 70 results in receipt of the fingers 116 inthe recesses 117. The rings 106 and 107, of course, could be reversed onthe spindle and the cartridge. Selected circumferential repositioning ofcomplementary upper and lower adaptor rings 106 and 107 may be utilizedto provide a proprietary fit for selected customers. To establish adesired position and a proprietary fit, the position of the fingers 117and recesses 118 can be varied circumferentially, using a locater 119for the spin welding fixtures. Further, the radial position of thefingers and recesses can be changed together, e.g. to the center orinner edges of the rings to provide a wide range of proprietary fits.Proper engagement of the rings, of course, also assures compatibility ofthe cartridge with the filter head.

In another embodiment, shown in FIGS. 6, 8A, 8B, 11A and 12A, the upperadaptor ring 106 a is secured to the shoulder 108, as described withrespect to the previous embodiment. Likewise, the adaptor ring 106 a hasan integral weld flange 111 a and the mounting shoulder 108 is providedwith a complementary weld groove 112. Similarly, the lower adaptor ring107 a is mounted on the shoulder 113 on the cartridge body nick aboutthe connector lugs. The lower adaptor ring 107 a has an integral weldflange 114 a that seats in the complementary weld groove 115 in theshoulder 113. Both rings 106 a and 107 a may be secured to therespective shoulders 108 and 113 by spin welding (or other suitablewelding process). The exposed lower face of the upper adaptor ring 106 ais non-planar and defines a pair of diametrically opposite, axiallyextending abutment faces 116 a. Similarly, the exposed upper face of thelower adaptor ring 107 a has a pair of diametrically opposite andaxially extending abutment faces 117 a. As with the previously describedembodiment, the upper and lower adaptor rings 106 a and 107 a arelocated in circumferentially precise and complementary positions toensure engagement of the abutment faces 116 a and 117 a when thecartridge is attached to the filter head and the mounting ring. On theupper adaptor ring 106 a, the abutment faces 116 a are defined byprotrusions 118 a on the ring body and, on the lower adaptor ring 107 a,the abutment faces 117 a are defined by recesses 120 a in the ring body.

A presently preferred arrangement for assuring compatibility andoperative connection of the cartridge to the filter head is shown inFIGS. 31-36. This arrangement utilizes the same filter head 26 andspindle 70 which together are attached to and carried by mounting ring25 on the mounting bracket 24. Similarly, the filter head and mountingbracket are designed to accept the standard filter cartridge 11, all aspreviously described.

Referring first to FIG. 31, the shoulder or end face 113 on thecartridge neck 75 is provided with a pair of diametrically oppositevertically extending unlocking pins 243. The shoulder 113 may beprovided with a circular array of holes 244 into which the reduceddiameter ends 245 of the pins may be press fit. For example, if thecartridge shoulder has 14 equally spaced holes 244, diametricallyopposite pairs of pins 243 could be placed in seven differentcircumferential positions.

Alternately, the pins 243 could be formed integrally with and carried ona lower adaptor ring (not shown) similar to the adaptor ring 107 a shownin FIG. 8A. The adaptor ring would be attached to the cartridge shoulder113 by ultrasonic or other welding process, as previously described.

Referring also to FIG. 32, a lowermost shoulder 246 on the spindle 70 isprovided with a pattern of through bores 247 into and through which thepins 243 on the cartridge neck are permitted to pass when attaching thecartridge to the filter head 26. The pattern of through bores 247matches the pattern of holes 244 for unlocking pins 243.

An upper adaptor ring 248 is captured between shoulder 246 on thespindle 70 and a vertically adjacent shoulder 250 on the filter head 26.The upper adaptor ring 248 has a lower face 252 that is attached to theupper surface of the spindle shoulder 246 in a manner that causes theadaptor ring 248 to rotate with the spindle 70, but is not fixedlyattached to the spindle. However, because the ring is captured betweenthe shoulders 246 and 250, the lower face 252 of the adaptor ring may beselectively attached to the spindle shoulder with a diametricallyopposed pair of bosses 253 that are received in recesses 254 in thespindle shoulder 246. The recesses 254 are provided in a fullcircumferential pattern corresponding to the circular pattern of throughbores 247 in the spindle.

The adaptor ring 248 has a pair of diametrically opposed through holes256 into which locking detents 257, in the form of spring biased pins258 extend. The locking pins 258 are mounted in blind bores 260 in thelower face 259 of the housing shoulder 250. The blind bores 260 areformed in a circular pattern that matches, in number and spacing, thepattern of through bores 247 and the recesses 254 in the spindleshoulder 246. The position of the pair of spring biased pins 258 on theface 259 of the shoulder is selected to correspond to the location ofthe through holes 256 in the adaptor ring 248 and the location of thepair of pins 243 on the cartridge neck 75. When the locking pins 258extend through the holes 256 in the upper adaptor ring, as best seen inFIG. 31, the spindle 70 cannot turn axially in the head 26. This, ofcourse, prevents attachment and operative engagement between the filtercartridge and the head.

FIGS. 31, 32 and 34 show the progression of unlocking the locking pins258 by insertion of the filter cartridge with the cartridge unlockingpins 243 properly oriented circumferentially to match the adaptor ringholes 256 and the position of the pair of locking pins 258. As thefilter cartridge 11 moves vertically through the mounting ring 25 andinto the spindle 70, the pins 243 will be received and pass into thethrough bores 247 in the spindle. Because, as previously explained,connection of the filter cartridge to the spindle and head follows apath of simultaneous rotational and axial movement, the lower surfacesof the through holes 247 are provided with ramp surfaces 261 to permitsmooth transition of the pins 243 into and through the bores 247. Theends of the pins 243 pass into relieved areas 262 in the bottom ends ofthe through holes 256 in the adaptor ring and engage the ends of lockingpins 258, forcing the locking pins to move vertically upwardly againstthe bias of the bias springs 263. Continued axial rotation of thespindle and adaptor ring causes the ring to under ride the ends of thelocking pins 258, forcing the pins to ride upwardly over the chamferededges 264 of the adaptor ring, until the locking pins are fullywithdrawn from the holes and ride on the upper surface 255 of theadaptor ring.

To assure compatibility of the cartridge with the filter head and/or toprovide a proprietary arrangement for a selected customer or user,circumferential positions of the pins 243 and adaptor ring holes 256,are selected to match the circumferential positions of the blind bores260 in which the pair of locking pins 258 are mounted. As indicatedabove, with a pattern of holes 247 in the spindle shoulder 246 of 14holes, the cartridge pin pair 246 can be matched with the locking pinpair 258 to provide 7 different positions for a proprietary fit. Holepatterns with more or fewer arrangements may be used and, to increasethe number of matching fits between the cartridge and the head, thecross sectional shapes of the pins 243 and receiving holes 247 couldalso be varied.

If one of the filter cartridges 11 is a reverse osmosis (RO) cartridge,such as second cartridge 16 in the filter system 10 shown in FIG. 1, allof the basic elements including the filter head, spindle, mounting ringand cartridge are of different constructions than the correspondingelements in the system described thus far. The need for different sizeand shape of the parts for an RO system is related to the need to handlethree separate flows of water, namely, the inlet water to be treated bymembrane separation, the product water or permeate after passage throughthe membrane, and the brine or retentate carrying the dissolved solidsin a relatively high volume of water.

Referring initially to FIGS. 13, 14, and 19, an RO cartridge 121 has agenerally cylindrical body 122 carrying a cylindrical filter element 123and having a neck 124 on one end by which it is fastened to a mountingring 125 and filter head 126. The filter head 126 carries a valvespindle 127 that provides a flow control function in a manner similar tothe spindle 70 of the previously described embodiment. However, the ROspindle 127 also provides a flow path for the brine flow and a controlvalve for regulating the flow of product water to and from a storagetank.

The RO unit is supported on a mounting bracket 128 with the samerectangular base permitting direct attachment to a modular back plate 18described above. The mounting bracket 128 also includes the integralmounting ring 125 that provides attachment of the filter head 126 andspindle 127 from above and the demountable attachment of the ROcartridge 121 from below in a manner similar to the mounting arrangementused with the previously described embodiment. However, this filterarrangement also provides for the separate removal of the spindle 127,after removal of the filter cartridge 121, as will be described ingreater detail below.

The RO cartridge 121 may be of a generally well known construction,including an interior spirally wound semi-permeable membrane 131 thatincludes an intermediate separator layer wound around a central hollowproduct water tube 132. The product water flows radially inwardly,enters the product water tube 132 through holes therein, and then flowsvertically upwardly along the interior of the tube and into the ROfilter head 126. The brine flow (high volume membrane concentrate ofwater and dissolved solids) which does not pass through the membrane,flows vertically downwardly and exits the filter element 123 at thebottom end. The volume of brine may comprise as much as 80% of the totalincoming flow volume of pre-filtered water, but the proportions maychange depending on other changes in system operation.

The upper end of the RO filter element 123 is enclosed with an end cap134. The end cap 134 functions to help control the flow of water throughcartridge 121 and also provides a positioning function to assure propercartridge fit and function in a manner similar to the previouslydescribed embodiment.

Incoming water enters the filter head 126 via an inlet sleeve 135. Withthe spindle 127 rotated to the open or flow position, incoming waterpasses from the inlet sleeve 135 through an inlet opening 136 in thewall of the filter head 126, and continues through an inlet 137 in thespindle 127. System pressure acts on one diaphragm of a double diaphragmvalve 138, causing it to unseat and to permit incoming water to flowvertically downwardly through an inlet passage 140 and through anopening in the end cap 134 of the filter element 123. The water thenpasses through the RO filter element 123, as previously described, whereit is divided into a product water (permeate) flow and a brine(retentate) flow. These two flows are returned to the filter head viathe spindle 127 for further processing as follows.

Referring particularly to FIG. 14, the lower end of the spindle 127 hasa downwardly depending outer skirt 141 that seals against the outside ofthe cartridge neck 124 and against the inside of end cap 134. Anintermediate skirt 142, coaxial with the outer skirt 141, provides aflow channel for water from the inlet 137. A brine flow passage 143(FIG. 15A) on the outside of the outer skirt 141 provides an inlet tothe spindle for brine exiting the filter. The intermediate skirt 142 issealed on the inside to the outside of the product water tube 132. Aspindle inner skirt 144 has, in its lower inlet end, a porouspolypropylene disk 145 that provides the same anti-drip function as thedisks 104 and 105 described for the prior embodiment. Above the porousdisk is a check valve 146 that prevents the back flow of treated productwater into the RO cartridge 121, as will be described in great detailbelow. The product water flows through a vertical product water passage147, a cross passage 149 in a removable closure plate 153, and thenvertically into a chamber 148 in the closure plate 153 where the productwater is exposed to the face of the outside diaphragm 154 of the doublediaphragm 138. From the chamber 148, the product water flows through anoutlet 150 in the closure plate 153, and an outlet opening 151 in thefilter head, which opens directly to the outlet sleeve 152.

The higher volume brine flow, passing out of the RO cartridge 121between the cartridge neck 124 and the outside of the spindle outerskirt 141 passes into the spindle body via the radial passage 143 in theupper portion of the outer skirt 141. The radial passage 143 joins avertical passage 156 into the spindle body to a second radial passage157 where the brine flow exits the spindle body and enters a large openarea chamber 160 between the spindle body and the inside wall of thefilter head 126. The brine flow continues generally vertically to aradial outlet passage 158 where the brine flow exits the large open areaand re-enters the spindle body via an outlet passage 158 thatcommunicates with an open upper chamber 161 at the top of the spindle127. The upper chamber is sealed from the large open brine-containingchamber 160 below and is enclosed by a filter head top cap 162. Brineflow exits the upper chamber 161 via a brine outlet opening 163 in thefilter head and an integral brine outlet sleeve 164.

Returning again to FIGS. 13 and 14, the flow of product water exitingthe filter head 26 via the outlet sleeve 152 may be directed to apressurized storage tank in a manner well known in the art. The storagetank typically includes an interior flexible bladder or wall to one sideof which the product water flows and on the other side of which is anair space. As product water fills the storage tank and presses againstthe flexible bladder, the air on the opposite side is compressed and,therefore, the purified product water is stored under pressure. Othermeans for pressurizing the stored product water are also known. When thepressure in the storage tank reaches a desired level, the storage backpressure acts on the outside diaphragm 154 of the double diaphragm valve138 to overcome the counter-pressure of pre-filtered inlet flow againstthe opposite inside diaphragm 139, causing the latter to move againstits seat and to shut off the incoming flow from the inlet sleeve 135. Asis known in the art, the areas of the respective inside and outsidediaphragms 139 and 154 may be chosen to match a desired maximum storagetank pressure to the usual incoming line pressure, e.g. the pressure ofthe municipal supply of water. With a typical municipal water supplypressure of 60 psi and a desired storage tank pressure of 40 psi, thearea of the outside diaphragm 154, exposed to storage tank pressure,would be about two-thirds the area of the inside diaphragm 139, exposedto incoming line pressure. At about 40 psi of storage tank pressure, the60 psi inlet line pressure would be overcome and the shut off valve 46would close.

The radial outlet passage 158 from which brine flows out of the largeopen chamber 160 between the outside of the spindle and the inside ofthe filter head 126 is provided with a flow restrictor 165. The flowrestricted may be of any convenient construction which will create abrine back pressure sufficient to cause a desired volume of water to beforced through the RO membrane to generate the product water permeate.For example, the restrictor may comprise a ball valve and seat which isslotted to permit a restricted flow of brine past it. Generally, a ratioof brine-to-product water of about 5:1 to 4:1 is desirable. The ratiowill vary from initial start up as the increasing permeate back pressurefrom the pressurized storage tank counters inlet line pressure, therebyreducing permeate flow volume somewhat.

Referring also to FIGS. 16 and 17, the RO cartridge 121 and RO filterhead 126 require a different mounting bracket 128 and integral mountingring 125 than are used with the previously described filter cartridge 11and filter head 26. However, the differences are primarily in size and,as will be described, the RO cartridge 121 and associated filter head126 are attached to the RO mounting ring 125 in substantially the sameway. The mounting bracket 128 is attached to the same back plate 18 toprovide the modular assembly of a filter system as is the previouslydescribed mounting bracket 24.

The RO filter head 126 has an outer housing 168 that includes acylindrical bottom skirt 170 having an outer diameter larger than theupper portion of the outer housing 168. The lower edge of thecylindrical skirt 170 is provided with a pair of diametrically oppositemounting lugs 171 and 172. The mounting ring 125 has a generally openannular interior, including an outer wall 173 sized to receive thecylindrical bottom skirt 170 of the filter head housing. The upper edgeof the mounting ring outer wall 173 includes a pair of inwardly openingslots 174 and 175, respectively, for receipt of the mounting lugs 171and 172. Mounting lug 171, which is positioned below the inlet sleeve135, is provided with an open gap 176. The slot 174 in the mounting ringouter wall 173 has a protrusion 177 that is sized to move axiallythrough the gap 176 as the housing cylindrical skirt 170 moves axiallyinto the mounting ring 125. The opposite mounting lug 172 has no gap andthe corresponding slot 175 does not have a protrusion. As a result, thefilter head 126 can only be inserted into the mounting ring at onecircumferential position. As the cylindrical bottom skirt 170 of thefilter head drops through the slots, the lower edge comes to rest on acircular track 178 on the interior of the mounting ring. The track 178defines the bottom of an annular slot 180 having a height just largerthan the thickness of the mounting lugs 171 and 172, such that when thefilter head is rotated on the circular track 178, the lugs 171 and 172pass into the annular slot 180 until the filter head is in the operativeposition with the axis of the coaxial inlet and outlet sleeves 135 and152 parallel to the mounting bracket 128. In this operative position, apair of diametrically opposite stop detents 181 on the outer surface ofthe cylindrical skirt 170 engage respective first stops 182 in thecircular track 178 to prevent reverse rotation and establish theoperative position of the filter head. Further, a pair of diametricallyopposite locking detents 183 on the cylindrical skirt 170 immediatelyabove the mounting lugs 171 and 172 engage respective second stops 184on the circular track to prevent continued rotation of the filter headand to lock it in its operative position. Preferably, the stop detents181 have ramped surfaces permitting them to ride along the circulartrack 178 under the force of manual rotation of the filter head in themounting ring until the stop detents 181 snap into engagement with theirrespective stops 182. In this position, the locking detents 183 reachand simultaneously engage the second stops 184 establishing the lockedoperative position of the filter head.

The RO filter head 126 is made to permit removal of the spindle 127 inthe event it is necessary to replace the double diaphragm shut off valve138. The following comments describe first how the RO spindle 127 ismounted in the filter head 126 and how the RO filter cartridge 121 isattached to the mounting ring 125 and operatively connected to thefilter head and spindle. The upper end of the spindle 127 is providedwith an annular locking groove 185 (see FIGS. 13 and 14) positionedimmediately above an upper O-ring seal 186 that seals the upper chamber161 from the large open area chamber 160 below. Similarly, a lowerO-ring seal 187 provides a sealed interface between the spindle and theinterior of the filter head 126, thereby sealing the vertical chamber160 surrounding the spindle 127. That chamber also includes the waterinlet 137 and the axially aligned outlet 150, the latter of which, asdescribed above, is actually formed in the closure plate 153. The bodyof the spindle 127 is provided with a seal arrangement that creates awater tight interface between the spindle body and the cylindricalinterior wall 188 of the filter head 126. In addition to the upper andlower O-ring seals 186 and 187, the sealed interface includes a dualfunction seal 190 for each of the inlet 137 and outlet 150 in thespindle and the corresponding respective inlet opening 136 and outletopening 151 in the filter head 126. The dual function seal 190 issimilar in construction and function to the seal 94 (see FIG. 10) usedin the previously described embodiment. Thus, the dual function seal 190rotates with the spindle 127 between a flow position, wherein flow isenabled between the filter head and the cartridge as described above,and a no-flow position, wherein flow is halted. In both positions, thedual function seal separates the brine flow through the filter head andspindle from the flows of incoming water and product water.

Because the spindle 127 is designed to be removable for replacement ofthe diaphragm shut off valve 138, it is possible to mount the filterhead 126 to the mounting ring 125 with or without the spindle in placein the filter head. With the filter head 126 mounted in operativeposition to the mounting ring 125, as described above, the spindle 127is inserted axially from below through the mounting ring 125 and intothe filter head 126. Referring also to FIG. 20, the annular lockinggroove 185 in the upper end of the spindle is provided with an opennotch 191 sized to receive a lug 192 on the inside wall of the filterhead 126 just below the brine outlet opening 163. Receipt of the lug 192in the notch 191 permits the spindle to be fully inserted and the lug192 aligned with the annular locking groove 185. Rotation of the spindlecauses the locking groove to enclose the lug such that the spindle isrestrained from axial movement out of the filter head. The spindle maybe rotated with respect to the head and the lug 192 until the lugengages a stop 193 in the locking groove 185 after about 120° ofrotation. This places the spindle rotationally in the no-flow positionwhereupon the system water may be turned on to permit operation.

Referring also to FIGS. 16-18, the neck 124 of the RO cartridge 121 isprovided with a pair of diametrically opposed connector lugs 194,similar to the connector lugs 81 (see FIG. 8A) of the previouslydescribed embodiment. The connector lugs 194 have a parallelogram shapein cross section defined by narrow leading and trailing edges 195, inthe rotational direction, that define cam surfaces 196. The circulartrack 178 in the outer wall 173 of the mounting ring 125 has a pair ofdiametrically opposed slots 197, each of which has angled contactsurfaces 198 that define openings through which the connector lugs 194on the filter cartridge neck may pass. As the filter cartridge neck isinserted axially into the mounting ring and spindle, simultaneousrotation of the cartridge to the right (clockwise direction) permits theleading cam surfaces 196 on the connector lugs to ride upwardly over thecontact surfaces 198, into the mounting ring 125 and onto the circulartrack 178. As the connector lugs reach this position, their lead edgesengages the vertical drive faces 200 of a rotatable spindle drive ring201 (FIG. 21) that is captured in the interface between the filter headouter housing 168, the mounting ring 125 and the spindle 127. Moreparticularly, and referring also to FIGS. 14, 15A and 15B, the spindledrive ring 201 rests on an annular shoulder 202 on the cylindricalinterior wall 188 of the filter head 126. The drive ring 201 carries anupper O-ring seal 203 that seals against the cylindrical inner wall 188of the filter head. The interface between the drive ring and the spindleis sealed by the lower O-ring seal 187. A lower flange 205 on thespindle that defines one wall of the groove carrying the lower O-ringseal 187 is provided with a pair of diametrically opposite drive tabs204 (FIGS. 20 and 26). With the drive ring 201 seated on the shoulder202, insertion of the spindle through the drive ring and into the filterhead permits the drive tabs 204 to drop into shallow notches 206 in theinterior of the drive ring. If necessary, continued rotation of thespindle and the drive ring will permit the notch 191 in the annularlocking groove 185 at the upper end of the spindle to engage the lug 192on the interior of the filter head to establish the proper axialposition of the spindle within the head and the drive tabs 204 to seatfully in the notches 206. From this position, axial rotation of thespindle and drive ring in the counterclockwise direction (clockwiserotation is prevented by stop wall 199 in the locking groove 185 at oneside of the notch 191) permits the annular locking groove 185 in whichthe lug 192 is seated to move relative to the lug until the lug reachesthe stop 193 in the groove 185 after about 120° of rotation. At thisposition, the spindle is in the no-flow position and the supply of watermay be turned on. As the filter cartridge 121 is inserted verticallythrough the tapered slots 197 in the mounting ring 125 and onto thecircular track 178, the lead edges of the lugs will engage the verticaldrive faces 200 on the spindle drive ring to cause rotation of thespindle from the no-flow to the flow position. Continued movement in theclockwise direction is prevented by engagement of the lead edges 195 ofthe connector lugs 194 with recessed stops 189 inside of the bottom edgeof the filter head bottom skirt 170. In this position, the lowermostedges 207 of the spindle drive ring 201 rest on the circular track 178and the recessed edges 209 rest on the top surfaces of the cartridgeconnector lugs 194.

Referring again to FIGS. 13, 15A and 15C, as well as FIGS. 22-25, the ROfilter cartridge 121 contains the filter element 123 that is insertedthrough the open bottom end of the cartridge body 122 and held in placewith a lower enclosing end cap 207. The upper end of the filter element123 is closed by the end cap 134 that has an outer flange 208 that isseated in the upper end of a brine ring 210 and sealed therein with anO-ring seal 211. The upper end of the end cap 134 has a narrower neck212, the outside of which seats an upper O-ring 213 that providessealing contact with the inside of the outer skirt 141 of the spindle127 when the cartridge is inserted through the mounting ring and intothe filter head. The O-ring seals 211 and 213 preclude brine water frommixing with the incoming water and product water, and assure that thebrine flow is directed to the brine flow passage 143 in the spindleouter skirt 141. Separation of the incoming water flow from the productwater flow is accomplished by a double O-ring seal 214 carried on theproduct water tube 132 that engages the inside surface of the spindleinner skirt 144.

The RO cartridge 121 and valve spindle 127 include a locatorarrangement, similar to that used in the previously describedembodiment, to assure filter cartridge compatibility and operativeconnection of the cartridge 121 to the filter head 126. This arrangementmay also be utilized to provide a proprietary filter assembly for aselected distributor or dealer, as also previously described above.

A lower adaptor ring 215 (FIGS. 23 and 24) seats on an interior shoulder216 on the inside of the neck 212 of the end cap 134. The ring 215 hasan integral finger 217 extending perpendicular to the plane of the ring.The ring may be secured on the interior shoulder 216 by spin welding,ultrasonic welding or other suitable fastening process. The end capouter flange 208 is provided with a locator notch 218. Upon assembly ofthe filter element 123 into the cartridge body 122, the locator notch218 is positioned to engage a matching protrusion on the inside of theneck 124 of the filter cartridge body. This assures propercircumferential location of the finger 217. A complementary upperadaptor ring 220 (FIGS. 25 and 26) is seated on a shoulder 221 on theinside of the spindle outer skirt 141. The inside edge of the upperadaptor ring 220 is provided with a circumferentially extending cutout223 which, in turn, has a centered notch 222 that is sized to receivethe finger 217 extending from the lower adaptor ring 215. The upperadaptor ring 220 may also be affixed on the shoulder 221 by spin weldingor other suitable plastic welding process that positions the notch 222such that, when the cartridge is attached to the filter head with thespindle 127 in the locked off position, the finger 217 will engage thenotch 222. By adjusting the circumferential positions of the finger 217and the notch 222. By accurate control of the welding process, a numberof proprietary adaptor ring positions may be provided that can be usedto offer a customer a proprietary product.

Referring particularly to FIGS. 13, 26 and 27, when it is desired toremove the spindle 127 to, for example, replace the diaphragm valve 138,it has been found that the many sealed interfaces between the spindleand the head 126 make it difficult to remove the spindle. To facilitatespindle removal, a special spindle removal tool 224, as shown in FIG.27, may be used. After the RO cartridge 121 has been removed and thesource of water has been shut off, the removal tool 224 is inserted intothe spindle with the inner spindle skirt 144 received in the hollowinterior of the tool body 225. A curved offset 226 on the inner end ofthe tool body is sized to fit into the cutout 223 in the adaptor ring220. When the curved offset 226 is centered in the cutout, engagementlug 227 at the end of the offset 226 will pass through the notch 222 inthe cutout 223. Slight rotation of the tool in either direction willcause the engagement lug 227 to move out of alignment with the notch 222and to engage the underside of the ring 220. The user may then pullaxially on the tool handle 228, after first rotating the tool in the“on” direction to permit the retaining lug 192 in the upper part of thefilter head 126 to pass through the notch 191 in the locking groove 185.

To further facilitate removal of the spindle 127 from the filter head126, and referring also to FIG. 17, a large portion of the cylindricalinterior wall 188 of the filter head has a recessed cylindrical surface229 that has a larger diameter than the sealing surfaces 219 that makesealing contact with the dual function seal 190. When the spindle isrotated to the removal position, dual function seals 190 will engage therecessed surface where the force necessary to remove the spindle issubstantially reduced.

Referring to FIG. 8B and also to FIGS. 28-30, the filter element 78 isassembled into the cartridge 11 utilizing a unique filter elementpositioning and stabilizing method. The filter element 78, which maycomprise a granular activated carbon or porous carbon block filterelement is inserted axially through a bottom opening 230 in thecartridge body 74. The filter element 78 has an upper end cap 231 thatengages the inside of the cartridge neck 75. Specifically, the upper endcap 231 engages four equally spaced circular flats 232 to provide a stopto further axial movement in the upward direction. The filter element 78is secured within the cartridge body 74 with a bottom end cap 233 that,in the preferred embodiment, is spin welded to the bottom opening 230.The bottom end cap 233 has a centering post 239 that engages a centerrecess 241 in an end closure 242 of the filter element 78. In order tofacilitate spin welding, it is desirable to attach the bottom end capwith the filter cartridge assembly positioned vertically. This, in turn,requires that the filter element 78 be retained against downwardvertical movement until the bottom end cap 233 has been successfullyspin welded to the opening 230 in the cartridge body 74. The upper endcap 231 includes an upwardly extending filter neck 234 that defines thewater inlet 76 and outlet 77, the upper end of the former provided withan upper O-ring seal 235 that engages the interior of the spindle body71. The lower portion of the filter neck 234 is provided with a lowerO-ring seal 236 that provides sealing contact with the interior ofcartridge body neck 75. To retain the filter element 78 for the spinwelding process, after insertion of the element axially into the filterbody against the flats 232, a retaining ring 237 is inserted in acircular groove 238 in the portion of the neck just above the upper endof the cartridge body neck 75. The groove 238 for the retaining ring 237is shallow and results in the retaining ring extending radially over theinner edge of the top end of the neck 75. The retaining ring 237provides a positive stop against reverse axial downward movement of theelement in the cartridge body, thereby enabling the spin weld process tofully and securely enclose the bottom of the cartridge. The retainingring 237 provides no sealing function and may be left in place when thecartridge is attached to the filter head 26.

The cartridge bottom end cap 233 is preferably partially enclosed by acap grip ring 240 that is snapped over the peripheral edge of the bottomend cap. The grip ring 240 is made of a softer rubber-like plastic tofacilitate gripping by the user for cartridge installation or removal.Further, the grip ring 240 may be colored to provide a code to assistthe user in selecting and installing the proper filter cartridge.

1. A method for assembling a water filter element in a housing toprovide a replaceable filter cartridge, the housing having an openoperative end defined by an annular reduced diameter portion and thefilter element having an end enclosure with an axially extending necksealingly engaging the interior of the reduced diameter portion,extending axially therepast to a stop position in which the end closureis in engagement with the housing, and having an inlet and an outlet forwater, the method comprising the steps of: (1) providing the oppositeend of the housing with an annular opening for receipt of the filterelement; (2) inserting the filter element axially through the annularopening until the element reaches the stop position; (3) attaching aretaining ring to the neck of the filter element at a position axiallybeyond and in engagement with the end of the reduced diameter portion ofthe housing when the filter element is in the stop position to retainthe element from reverse axial movement; and, (4) attaching a housingend cap to the housing annular opening to seal the opening and hold thefilter element in the stop position.
 2. The method as set forth in claim1 including the steps of: (1) providing an annular groove in the neck ofthe element; and, (2) placing the retaining ring in the annular groove.3. The method as set forth in claim 2 wherein the retaining ringcomprises an O-ring.
 4. The method as set forth in claim 1 wherein thestep of attaching the housing end cap comprises spin welding.
 5. Themethod as set forth in claim 1 including the step of attaching a capgrip to the housing end cap.
 6. The method as set forth in claim 5including the step of coding the cap grip with cartridge identificationindicia.
 7. The method as set forth in claim 5 wherein the coding stepcomprises color coding.
 8. The method as set forth in claim 5 whereinthe cap grip attaching step comprises snap fitting.
 9. The method as setforth in claim 5 including the step of providing the cap grip with ahigh friction surface to enhance manual gripping.
 10. A subassembly foruse in the assembly of a replaceable filter cartridge comprising: acylindrical housing having an open operative end defined by an annularreduced diameter portion and an annular opening in the opposite end of adiameter larger than the diameter of the open operative end; a filterelement positioned in the housing and having an end closure with anaxially extending neck in sealing contact with the interior of thereduced diameter portion, and a major diameter smaller than the annularopening and larger than the open operative end, said filter elementpositioned in the housing against an axial stop to define an operativeposition; and, a retaining ring attached to the filter element neck at aposition axially beyond and in engagement with the end of the reduceddiameter portion of the housing to retain the element from axialmovement.
 11. The subassembly as set forth in claim 10 including abottom end cap attached to the opposite end of the housing to enclosethe filter element therein.
 12. The subassembly as set forth in claim 11including a grip ring attached to the peripheral outer edge of the endcap.